There are already several crashers on theme switching (e.g. bug 116038, bug
121638, bug 124009, bug 124205 and bug 125518)
A stack trace/talkback report would help considerably in figuring out whether
this is a duplicate of one of those, of another that I missed, or a new bug.

Severity: major → critical

CC: gav

Summary: Mozilla crashs if you are switching between classic and modern theme often → Mozilla crashes if you are switching between classic and modern theme often

I am closing this as invalid[1] due to lack of details.
Reporter: If you are able to generate a talkback incident or stack trace,
please re-open this bug and attach relevant details.
[1] sorry if "invalid" sounds harsh, but it's all bugzilla's got.